1. Field of the Invention
The present invention relates in general to the adjustment of an electro-hydraulic or electromechanical solenoid actuator, and in particular to a rack and pinion apparatus and method for adjusting an orifice or air-gap within the actuator or a solenoid on a real-time basis for calibration.
2. Description of the Related Art
Electro-hydraulic or electromechanical solenoid actuators, referred to herein as solenoids or solenoid valve assemblies or actuators typically need to have orifices and/or air-gaps within the valves or solenoids adjusted after assembly. Conventional manufacturing methods parts tolerancing usually provides an assembled position range larger than necessary for desired solenoid or actuator performance. A typical prior art method of adjusting an orifice or an air-gap is to provide a threaded portion accessible from outside the solenoid, insert a tool in a slot or receptacle, adjust the orifice or air-gap to a desired position by rotating the adjustment tool, removing the tool from the slot and then testing the solenoid to see if the calibration is acceptable.
As an example, U.S. Pat. No. 5,513,673 discloses an electrically modulated pressure regulator valve with a variable force solenoid. The solenoid valve assembly is provided with an adjustment screw for variably adjusting the axial overlap (or air-gap) between an armature body and the central bore of the adjustment screw. The axial overlap between the surface of the armature and the inner circumferential surface of the screw adjust can be adjusted by varying the position of adjustment screw relative to the closed end of the housing. This adjustment allows the working air-gap to be varied.
Similarly, in U.S. Pat. No. 4,947,893, the solenoid valve assembly includes an adjustment plug which provides means for variably adjusting the minimum working air-gap distance between the armature body member and flux collector. These patents are owned by the assignee of the present invention, and hereby incorporated by reference.
Adjustment of the orifice and/or air-gaps can be problematic in that the adjustment tool can block flows and pressures, and as such requires an offset calibration value to be used which may or may not be correlatable to preset standards. Furthermore, the adjustment tool as it engages and disengages the threaded portion can change the calibration before the adjustment is locked into place.
Thus, there still exists a need for an apparatus and method for adjusting an orifice or an air-gap within a solenoid valve assembly which results in a real-time directly measurable calibration. Preferably, such an apparatus and method would allow for adjustment on a real-time basis and would allow the positioner of the solenoid valve assembly to be secured or fixed in position while the adjustment tool is still engaged so that the adjustment is locked into place during calibration.
An object of the present invention is to provide an apparatus for adjusting a solenoid valve assembly for real-time calibration.
Another object of the present invention is to provide a method of adjusting a solenoid valve assembly on a real-time basis.
Still another object of the present invention is to provide an apparatus for adjusting a solenoid valve assembly on a real-time basis that employs a shaft with a pinion at one end.
Still another object of the present invention is to provide a rack/gear method for adjusting a solenoid valve assembly that moves the adjustment tool out of the functional flow area resulting in a real-time directly measurable calibration.
The present invention is directed to solving the aforementioned objects as well as others by providing an apparatus and method for adjusting an actuator or solenoid on a real-time measurable calibration basis. The apparatus of the present invention comprises an actuator having at least one chamber therein, with an adjustable member movably situated within the at least one chamber. The adjustable member includes threads that extend axially over a portion on an outer surface of the adjustable member. The actuator has a bore that extends from the threads on the adjustable member to an outer surface of the actuator. An adjustment member with a plurality of splines at one end is positioned within the bore for engagement of the splines with the threads on the adjustable member to provide for a real-time adjustment of the actuator to a desired position or setting.
The present invention also comprises a method of adjusting an actuator in real-time which includes the steps of providing a geared rack on a selected portion of an outer surface of an adjustable member in an actuator. An adjustment member is positioned within a bore in the outer surface of the actuator to engage the geared rack with a pinion on the adjustment member. The adjustable member is moved to a desired position or setting where it is then secured with a retainer.
The various features of novelty which characterize the present invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.